The present invention relates to a pulsator for milking machines and having two diaphragms connected by a rod, each diaphragm dividing a pressure chamber into a processing space and a damping space, the damping damping communicating through a channel that is provided with a throttle, and the processing spaces being connected either to a source of vacuum or to the atmosphere, with a switchover that is attached to the rod and that connects lines leading to the pulsation spaces of teat cups either to the atmosphere or to a source of vacuum, and with a main line that is provided with a throttle, the throttles in the communcating channel and in the main line being detoured by bypasses provided with chokes that can be vacuum-activated through control channels.
A pulsator of this type is known, for example, from European Pat. No. B 0 032 752. It is intended to essentially increase the number of pulsations per unit of time in the pulsation spaces while simultaneously decreasing the requisite pressure difference therein during the stimulation phase that precedes the actual milking process. The desired duration of stimulation is set in a timer and, once it expires, the chokes in the control lines are activated. The chokes consist of clamps that at least to some extent compress the control channels, which are flexible hoses, and close them off. Hoses of this type that are subject to mechanical stress, however, are very easy to damage, leading to breakdown of the pulsator.
The timers on the other hand necessarily involve precision mechanisms that make them sensitive to the conditions that commonly prevail in milking parlors, and can also lead to breakdowns.